Patent GB-190509405-A (GB)
Title: Improvements in Electro-magnetic Mechanism for Actuating Points or Switches of Electric Railways.
Inventor: KITT FREDERICK THEODORE
Filed: 1905-05-04
Granted: 1906-03-01
Abstract: 9405. Kitt, F. J. May 4. Electric railways and tramways on the overhead-conductor system. Points and switches.-In actuating electric railway points by electro-magnetic means, part of the trolly wire, on which the wheel comes just before arrival at the curve, is insulated, and the car current is caused to pass through solenoids which open or close the circuits of magnets governing the position of the rail tongue. The latter is thus put under the control of the driver, but cannot be set for the curve unless the speed is below a certain limit. In the arrangement shown in Fig. 1, the trolly wheel 52 is passing along the insulated wire 47 in the direction of the arrow and the car is just about to take the curve 6, the tongue 7 being set under the influence of the electro-magnet 16, which is coupled to it through the lever 10, pivoted at 12, and the connecting-rod 8. Current for the electro-magnet 16 passes from the trolly wire 45 through the conductors 42, 43, bridge-piece 22 carried by the core 23 of a solenoid 24, resistance 44, and conductor 19, and through the magnet winding to earth 18. Current for the solenoid 24 enters from the trolly wire 45 and terminal 41, and leaves by the terminal 40 and conductor 48 to the insulated wire 47, and so to the car controller and motors. When the car passes round the curve and the trolly leaves the wire 47, the circuit of the solenoid 24 is broken and the plunger 23 falls, opening the circuit of the magnet 16. In falling, a pin 30 carried by the upper non-magnetic part of the plunger 23, meets one of the notches 29 cut in the end of a fixed tube 27, of non-magnetic material, surrounding the-plunger, and causes the latter to make one-eight of a revolution. The pin 30 is thereby brought in position to bridge contacts 37, 38, one of which is connected through a resistance 55 and a wire 54 to the winding of the magnet 15 and so to earth 17, while the other leads by a wire 33 to an insulated contact plate 50, Figs. 2 and 8, mounted below the trolly wire opposite a similar contact 50, which is in conducting communication with the trolly wire. Figs. 6 and 8 show the detailed construction of these and the adjacent parts. The wire 47 is held by brackets 59 to an insulating plate 60 secured to the trolly wire 45. The contact 51 is similarly secured opposite to the contact 50, from which a wire 49 runs to the trolly wire. Guiding-shoes 64, 63, 62 are placed as shown. The arrangement is thus left so that when the next car arrives, the trolly wheel passing between the contacts 50, 51 energizes the magnet 15 through the conductors 33, 30, 54, without disturbing the plunger 23, and causes the tongue 7 to be set to direct the car straight. As the trolly now comes on the wire 47, the controller being turned on, the plunger is raised, the pin 31 meeting the lower notches 29 and causing it to make a further one-eighth of a revolution, so that the bridge-piece 22 lies at right-angles to the gap 20, 21 and does not close the circuit of the magnet 16. In order to do this, the controller must be turned off and on again before the trolly leaves the wire 47, when the plunger 23 will first fall and then rise again, turning one-eighth of a revolution at each movement and so closing the gap 20, 21. Should the speed be so great that the current, after being shut off, cannot be turned on again before the trolly leaves the wire 47, the car will be directed straight on, leaving the plunger down and the contacts 37, 38 disconnected from the pin 30. In order to prevent the altered condition in which the arrangement is now left from affecting the proper regulation of the next car, a second solenoid 34 is provided, permanently shunted between the contacts 37, 38, embracing the upper end of the plunger 23, which, as shown in Fig. 4, consists of magnetic portions A and C screwed to a central non-magnetic portion B. A separate short core D<2> with enlarged head D<1> rests in the end of the coil 34. Thus on the arrival of the third car, the coil 34 is energized through the contacts 50, 51, and lifts the plunger 23 so far that the pin 31 enters the notches 29 and gives it one-eighth of a turn, but the core D<2>, held down at the same time, checks the upward movement before the bridge-piece 22 meets the contacts 20, 21. When the trolly passes away from the contacts 50, 51, the plunger drops, thus leaving the conditions for the third car as for the second. A simpler form of the invention, in which the last-mentioned device is not used, is shown in Fig. 15. The magnets 15, 16 are energized from the trolly wire by a conductor O which divides into two branches L and M, with gaps J, Hand K, G. The electro-magnetic switch, simplified by dispensing with the upper coil, is reduced to the form shown in Fig. 11. Each time the controller is turned on and off while the trolly is on the wire 47, the bridge-piece 22 makes onequarter of a turn, cutting out one of the magnets 15, 16 and throwing in the other. A modified arrangement of tube and notches is shown in Fig. 14.